1. Field of the Invention
The present invention relates to an inclination angle adjusting device and a workpiece attaching device.
2. Description of the Related Art
In vertical surface grinders, a workpiece is attached on a workpiece attaching surface on a rotating table, and while the rotating table is rotated, the top surface of the workpiece is surface ground by a grinding wheel rotating about the vertical axis. When a crystal material such as a crystal wafer and a sapphire wafer is surface ground by such a vertical surface grinder, it is necessary to grind by setting the crystal orientation.
For this reason, a method adopted in this case is as follows: on a rotating table rotating about the vertical axis in parallel to a grinding wheel shaft supporting the grinding wheel, a workpiece attaching device provided angularly adjustably with a workpiece attaching section having a workpiece attaching surface on its top surface about the horizontal axis is used; the inclination angle of the work attaching surface is set to the crystal orientation of the workpiece by adjusting the angle degree of the workpiece attaching section relative to the rotating table; and in this state, the workpiece is rotated and ground.
In this type of workpiece attaching device, as an inclination angle adjusting system for adjusting the inclination angle of the workpiece attaching section, there have been conventionally proposed a seesaw system, a gear drive system, etc.
In the seesaw system, on one end side in a radial direction between a rotating table having a grinding reference surface substantially parallel to a grinding surface of a grinding wheel and a workpiece attaching section having a workpiece attaching surface on its top surface, a pivot section is placed and on the other end side, a height-adjustment screw mechanism is placed, respectively, and the height-adjustment screw mechanism is operated in the up-and-down direction to adjust the inclination angle of the workpiece attaching section about the horizontal axis of the pivot section, as taught in Japanese Published Unexamined Patent Application No. H10-15795.
In the gear drive system, the workpiece attaching section is pivotally mounted on the rotating table by the horizontal shaft in the radial direction, and also, a servo motor for driving the workpiece attaching section about the horizontal shaft via a worm gear mechanism is arranged on the rotating table, permitting a forward-and-backward drive of the servo motor to adjust the inclination angle of the workpiece attaching section about the horizontal shaft.
In the conventional adjusting systems (either in the seesaw system or in the gear drive system), the workpiece attaching section is swung or pivoted directly about the horizontal axis to adjust the inclination angle, and thus, it is difficult to adjust a minute angle degree.
Further, in the case of the seesaw system, there is a problem that the workpiece attaching section is supported on the rotating table via the pivot section and the height-adjustment screw mechanism, and thus, it is difficult to secure the rigidity of the whole workpiece attaching device, making it impossible to grind the workpiece with high accuracy.
Also in the case of the gear drive system, there is a shortcoming that the workpiece attaching section is supported by the rotating table via the horizontal shaft and the worm gear mechanism, and besides, there is a constant backlash in the worm gear mechanism, making it difficult to secure the rigidity of the whole workpiece attaching device like the seesaw system. Another shortcoming is that the worm gear mechanism and the servo motor are provided on the rotating table rotating about the vertical axis, and thus, the size of the whole workpiece attaching device becomes too large.
In view of the conventional problems, an object of the present invention is to provide an inclination angle adjusting device and workpiece attaching device which is capable of facilitating the adjustment of a minute angle degree with high accuracy and also sufficiently securing the rigidity of the whole device after the adjustment and which can provide good operability, accuracy, and rigidity.